Hi Jagan,
Please find below the links to the documents which might help you understand the integration:
https://www.cisco.com/c/en/us/support/docs/unified-communications/unity-connection/118828-config-cuc-00.html
http://d2zmdbbm9feqrf.cloudfront.net/2012/usa/pdf/BRKUCC-2725.pdf
Regards,
Aseem Anand
(Please rate if it helps)